The use of waste of some Egyptian granitoids as a component in the production of ceramics.

Abstract

This thesis focuses on studying different types of Neoproterozoic granitoid rocks in south Sinai, central and south Eastern Desert together with the recycling of their wastes to use it in the production of ceramic material (lightweight aggregate). Tenareas with different varieties of rocks are chosen to achieve the aim of the study. These areas are wadi El Sheikh and Serbal in south Sinai; Abu Ziran, Fawakhir, Um Had and Umm Effein in central Eastern Desert and El Hudy, Aswan granite, Halaib and Wadi Kreiga in south Eastern Desert. To differentiate betweenthe ten granite plutons, petrological, geochemical and remote sensing studieswere used. The petrographic and geochemical studies showed that the samples of Wadi El Sheikh are granodiorite and tonalite whereas the rocks collected from Serbal is alkali feldspar granite and monzogranite. In central Eastern Desert, the rock samples of the four areas belong to granodiorite and monzogranite. While in south Eastern Desert, El Hudy and Aswan samples are monzogranite and granodiorite, respectively, whereas Halaib and Kreiga are granodiorite. The studied granitoids are created by partial melting either of metabasic to tonalitic sources (Wadi El Sheikh, Halaib, Abu Ziran and Kreiga), or metagreywaks sources (Serbal, Fawakhir, Um Effein, Um Had, El Hudy and Aswan). These granitoid rocks are suitable to be quarried as ornamental stones. The process of cutting, sawing and polishing generates large amounts of granitic wastes. Our purpose is to reuse the ornamental stone granitic wastes to produce lightweight aggregates. In order to attain this, six batch compositions were prepared in different proportions with the addition of Helwan clay to the granitic wastes. The raw materials and the lightweight aggregates are characterized using X-ray powder diffraction (XRD), X-ray fluorescence (XRF), differential thermal analysis (DTA), transmitted light (TLM), cathodoluminescence (CL)and SEM microscopy attached with energy dispersive X-ray analysis (EDAX) and X-ray micro-computed tomography (3D-mXCT). The results revealed that the contents of silica, alumina and total fluxes control the amount and viscosity of the liquid phase inside the aggregates during firing. The bloated aggregates show decrease in bulk density when the temperature and clay content increase.The microstructural, mineralogical and microchemical analyses show that a glassy phase is the major component in thelightweight aggregates.The highly viscous melt, developed during firing, is the main reason for the smallhomogeneous pores in the blank sample. In contrast, the lower viscosity of the melt in the 1:1 sample isresponsible for the existence of larger bubbles. All the prepared aggregates after firing at 1200 °C arelightweight aggregates which could be used in lightweight concrete as thermal and acoustic insulators.